The present invention relates to a laser instrument for electro-optical measurement of the distance of a target object to a reference mark comprised of a housing, a measuring device, which emits a laser beam and determines a distance value from the receiving beam coming from the target object, an outlet opening to couple out the laser beam from the housing, a display device to display the distance value and an operating device to operate the laser instrument and to start a distance measurement, wherein the display and operating devices are arranged on an upper side of the housing.
Laser instruments for optical distance measurement (called laser distance meters in the following) are known from the prior art and are marketed commercially. These laser distance meters emit a modulated laser beam, which is aligned on the surface of a target object, whose distance from the laser distance meter is being determined. The light of the laser beam reflected or scattered by the surface of the target object, called the receiving beam in the following, is detected by the laser distance meter and used to determine the distance. The field of application of these types of laser distance meters as a rule includes distances of several centimeters to several hundred meters. The laser distance meters known from the prior art can be divided into two categories in accordance with the arrangement of the transmitting and receiving devices: biaxial arrangements and coaxial arrangements.
FIG. 1a shows a known laser distance meter 1 having a measuring device 2, which aligns the laser beam 3 on a target object 4 and determines a distance value from the light of the laser beam reflected or scattered by the target object 4, which is designated as the receiving beam 5, and having a display device 6 to display the determined distance value as well as an operating device 7 to operate the laser distance meter 1 and to start a distance measurement. The laser distance meter 1 also has an optical sighting device 8, which is supposed to facilitate distance measurement especially in the case of outside measurements or with poor visibility conditions, when the laser beam 3 is hard to see on the target object 4 with the naked eye or is not visible at all.
The laser distance meter 1 is enclosed in a housing 9. The display and operating devices 6, 7 are embedded in an upper side 10 of the housing 9. In order to guarantee great ease of use when operating the laser distance meter 1 and displaying the distance value, the upper side 10 and the lower side 11 of the housing opposite from upper side 10 are the two largest housing surfaces of the laser distance meter 1. The front and rear sides 12, 13 adjacent to the upper side 10 as well as the side surfaces 14, 15 of the housing 9 are configured to be as small as possible in order to build a handy laser distance meter 1.
The laser beam 3 exits from the housing 9 via an outlet opening 16, which is arranged on the front side 12 of the housing 9, wherein the optical axis of the laser beam 3 is aligned approximately perpendicular with the front side 12. The receiving beam 5 coming from the target object 4 enters the laser distance meter 1 via an inlet opening 17, which is also arranged in the front side 12. In the case of the laser distance meter 1 depicted in FIG. 1a, the transmitting and receiving devices are arranged biaxially, i.e., their optical axes run parallel to one another, and do not overlap. As a result, the inlet opening 17 for the receiving beam 5 and the outlet opening for the laser beam 3 are arranged in the front side 12 separated spatially from each other.
Distance measurement to the target object 4 is carried out with respect to a reference mark located on the laser distance meter. In the case of the known laser distance meter 1, the front side 12, the rear side 13, a limit stop tip 18 or measuring extensions (not shown) are used as reference marks. Switching between the reference marks 12, 13, 18 is carried out via a switching device 19 or automatically, for instance if the limit stop tip 18 is folded out 180°.
FIG. 1b shows a schematic view of the interior of the laser distance meter 1 known from FIG. 1a with the measuring device 2, the optical sighting device 8 as well as the display and operating devices 6, 7. The measuring device 2 includes a transmitting device 20 with a beam source 21 and a first beam-shaping optical system 22, a receiving device 23 with a detector 24 and a second beam-shaping optical system 25 as well as an evaluation device 26. The evaluation device 26 is connected via communication connections 27a, 27b, 28 to the detector 24, the beam source 21 and the display device 6. It determines the distance value to the target object 4 from the time difference between the laser beam 3 emitted by the beam source 21 and the receiving beam 5 detected by the detector 4.
The optical sighting device 8 has a first optical element 29 and a second optical element 30. The user looks into the optical sighting device 8 via a sighting viewer 31, which is arranged in the side surface 14 of the housing 9. In this case, the user looks at the second optical element 30, which is configured to be predominantly transmittive for the laser wavelength and configured to be predominantly reflective for the wavelength range of the ambient light 32 being emitted by the target object 4. The ambient light 32 coming from the target object 4 arrives at the optical sighting device 8 with the image of the target object 4 via an inlet opening 33 in the front side 12 and hits the first optical element 29. From there it is deflected in the direction of the second optical element 30. Because the image of the target object 4 is reflected twice, at the first and second optical element 29, 30, an upright, un-reversed image of the target object 4 is produced, which the user perceives in the sighting viewer 31.
Arranged in the optical path of the laser beam 34 that is coupled out of the measuring device 2 is a beam splitter 35, which is preferably inclined at 45°to the optical axis of the laser beam 34. The beam splitter 35 is configured such that the predominant portion of the laser beam (e.g., ≧95%) passes through the beam splitter 35 as a transmitted laser beam 36, while the remaining portion (e.g., 5%) is deflected as the reflected laser beam 37. The reflected laser beam 37 penetrates the second optical element 30 of the optical sighting device 8 and can be perceived by the user as a lighter, almost punctiform spot of light. The second optical element 30 is configured such that it is transmittive for the laser wavelength λ and predominantly reflective for the wavelength range of the ambient light being emitted by the target object 4 except for a narrow range around the laser wavelength λ. When the user looks into the optical sighting device 8, he sees the image of the target object 4 and the spot of light of the reflected laser beam 37, which is located at the same position in the image of the target object 4 as the laser beam 3 on the surface of the target object 4. By positioning the point of light resulting from the reflected laser beam 37 in the image of the target object 4, the laser beam 3 is positioned precisely on the surface of the target object 4.
In the case of all commercially available laser distance meters, the outlet opening to couple out the laser beam, such as is the case with the laser distance meter 1 depicted in FIGS. 1a and 1b, is arranged on the front side of the housing and the distance measurement is carried out primarily with respect to the front and rear sides as reference marks. In the case of hand-operated laser distance meters, development is tending toward smaller and flatter devices. These smaller and flatter laser distance meters produce front and rear sides that are too narrow, which impede the positioning of the laser beam on the target object because, above all, in the case of an uneven substrate, a sufficiently stable level of the laser distance meter is not guaranteed. In addition, distance measurement is first possible for distances that are greater than the length of the housing.
In contrast, the object of the present invention is making a laser instrument for optical distance measurement available, in which a sufficiently stable level during distance measurement is guaranteed. In addition, distance measurement of small distances is supposed to be possible in cramped conditions.
This object is attained in accordance with the invention with the laser instrument for electro-optical distance measurement cited at the outset in that the outlet opening to couple out the laser beam is arranged in the upper side, in the lower side opposite from the upper side or in one of the side surfaces of the housing.
The arrangement of the outlet opening to couple out the laser beam in the upper side, in the lower side opposite from the upper side or in one of the side surfaces of the housing offers the advantage of a stable device surface at the reference mark. The surface on which the laser beam is coupled out of the housing and the housing surface opposite from this surface as well as measuring extensions serve as reference marks for the distance measurement. Because the display and operating devices are arranged in the upper side of the housing, the upper and lower sides, which are determined by the length and width of the housing, are as a rule the two largest housing surfaces. The side surfaces are defined by the length and depth of the housing.
At least one other outlet opening via which the laser beam can be coupled out of the housing is preferably provided in the housing. In the process, the outlet opening and the at least one other outlet opening are arranged in opposing surfaces of the housing in an especially preferred embodiment. This type of laser distance meter makes it possible to carry out distance measurements from one point to both sides in one spatial direction. This is advantageous if, for example, distances between target objects that are hard to reach are supposed to be determined.
In another preferred embodiment, the outlet opening and the at least one other outlet opening are arranged in adjacent surfaces of the housing. This type of laser distance meter makes it possible to carry out distance measurements from one point in two spatial directions. Calculations of area can be carried out via the evaluation device and the results are displayed to the user on the display device.
Three outlet openings are preferably provided to couple out the laser beam from the housing. In doing so, in an especially preferred embodiment, a first outlet opening is arranged in the upper or lower side, a second outlet opening is arranged in one of the side surfaces and a third outlet opening is arranged in the front or rear side of the housing.
This type of laser distance meter offers the possibility of carrying out measurements starting from one point in all three spatial directions without the laser distance meter having to be readjusted. Calculations of area or volume can be carried out via the evaluation device and the results are displayed to the user on the display device.
A switching device is preferably provided to change the operating mode of the laser instrument from a first operating mode in which the laser beam can be coupled out via the outlet opening to at least one other operating mode in which the laser beam can be coupled out via the at least one other outlet opening. It is particularly preferred that the switching device be configured in such a way that pivoting optics are moved from a first position into at least one other position when actuating the switching device, wherein the first and the at least one other position are configured such that the laser beam can be coupled out of the housing via the outlet opening or via the at least one other outlet opening. By switching between different outlet openings using the switching device, it is possible for the user to adapt the laser instrument to local circumstances.
In a preferred embodiment, a signaling device is provided, which displays the selected outlet opening, wherein the signaling device is arranged in particular in the upper side of the housing.
An optical sighting device having a first optical element and a second optical element is preferably provided.
Additional advantages and advantageous embodiments of the subject of the invention can be found in the description and the drawings. Similarly, the characteristics cited in the foregoing and those listed below according to the invention can respectively be used individually or multiply in any combination. The embodiments that are shown and described should not be understood as an exhaustive enumeration, rather they have an exemplary character in describing the invention.